For hatchlings, I like small tubs in commercially available rack systems.
For young juveniles, I've used 20G long glass aquariums, large (32-41 quart) tubs in commercially available rack systems, and 2 foot tall exo-terra glass vivariums. They've all worked great. For the glass cages, I've used ceramic heat emitters for heating. On my racks, I use flexwatt.
Right now I use Animal Plastics 4x2x2 caging for my largest carpet python. I'm thinking of selling that one however, and purchasing a stack of 4 foot long cages from http://www.constrictorsnw.com/cagess...prostacks.html and using pro heat radiant heat panels to heat them.